Kuo M Y, Chen H M, Hahn L J, Hsieh C C, Chiang C P
School of Dentistry, College of Medicine, National Taiwan University, Taipei.
J Dent Res. 1995 Nov;74(11):1783-8. doi: 10.1177/00220345950740111101.
To investigate the mechanism of collagen accumulation in oral submucous fibrosis (OSF) tissues, we examined the biosynthesis of collagen in fibroblast cultures established from OSF lesions. Fibroblasts obtained from four of ten OSF specimens showed more than a 1.5-fold increase in the production of collagens compared with fibroblasts from age-, sex-, and passage-matched normal controls (p < 0.05). When the relative amounts of collagen synthesis were estimated by SDS polyacrylamide gel electrophoresis, it was found that both OSF and control cells produced about 85% type I collagen and 15% type III collagen. The ratio of alpha 1(I) to alpha 2(I) chains was about 3:1 in OSF cells instead of the 2:1 expected for type I collagen. The excess alpha 1(I) chains could mean that collagen type I trimer was synthesized by the fibroblasts. These findings suggest that collagen overproduction and a reduced degradation of the structure-stable collagen type I trimer synthesized by OSF fibroblasts might contribute to the accumulation of collagen in OSF lesions in vivo. The mechanism(s) of increased procollagen production were analyzed by Northern blot, slot blot, and Southern blot. The OSF fibroblast strains with elevated collagen production also contained higher-than-normal levels of procollagen mRNA, and the ratios of alpha 1(I), alpha 2(I), and alpha 1(III) procollagen mRNAs were compatible with the results of corresponding procollagen alpha chains. The gene copy number of pro alpha 2(I) collagen gene in OSF fibroblasts was about 1.05. No gene amplification was found. These results indicate that expression of these procollagen genes in cultured fibroblasts is regulated at the transcriptional level.
为了研究口腔黏膜下纤维化（OSF）组织中胶原蛋白积累的机制，我们检测了从OSF病变组织建立的成纤维细胞培养物中胶原蛋白的生物合成。与年龄、性别和传代次数匹配的正常对照成纤维细胞相比，从10个OSF标本中的4个获取的成纤维细胞产生的胶原蛋白增加了1.5倍以上（p < 0.05）。当通过SDS聚丙烯酰胺凝胶电泳估计胶原蛋白合成的相对量时，发现OSF细胞和对照细胞均产生约85%的I型胶原蛋白和15%的III型胶原蛋白。OSF细胞中α1（I）与α2（I）链的比例约为3:1，而非I型胶原蛋白预期的2:1。过量的α1（I）链可能意味着成纤维细胞合成了I型胶原蛋白三聚体。这些发现表明，OSF成纤维细胞合成的结构稳定的I型胶原蛋白三聚体的过量产生和降解减少可能导致体内OSF病变中胶原蛋白的积累。通过Northern印迹、狭缝印迹和Southern印迹分析了前胶原蛋白产生增加的机制。胶原蛋白产生增加的OSF成纤维细胞株也含有高于正常水平的前胶原蛋白mRNA，并且α1（I）、α2（I）和α1（III）前胶原蛋白mRNA的比例与相应前胶原蛋白α链的结果一致。OSF成纤维细胞中前α2（I）胶原蛋白基因的基因拷贝数约为1.05。未发现基因扩增。这些结果表明，这些前胶原蛋白基因在培养的成纤维细胞中的表达在转录水平受到调控。
